By Danita Lee Ewing

One of the things that has come up several times over the last few years in the 1632 Tech Manual is questions about blood types and blood transfusion. Blood typing and blood products are important to medical care in the 163xverse because they can be so helpful to patients who have lost blood for whatever reason. Patients may lose blood due to surgery, trauma or chronic conditions such as Beulah’s stomach ulcer.

Blood has several parts and performs many functions in the body. The most well known are the Red blood cells which carry oxygen to the cells in the body. Without oxygen, the cells die. If a person loses enough red blood cells, they will die due to lack of oxygen to the cells in the rest of the body.

Less well known are the white blood cells. White blood cells come in a variety of types. Together, the white blood cells work in different ways to fight infection. Without these cells, germs would cause infections that would be lethal.

Plasma is the liquid part of the blood. Plasma has important chemicals in it that are delivered to the cells in the blood stream. It also carries the waste products ejected from the bodies cells to the liver and kidney where they are filtered out of the body.

At the end of this article is a glossary that has definitions of medical terms.

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Transfusions are a way to get needed blood into a person who doesn’t have enough blood to meet the body’s needs. The transfusion process is described in detail toward the end of the article. In short, a transfusion transfers blood, or blood parts from one person to another. If you randomly transfer blood between two people, there is an excellent chance that the recipient will die because the blood is not compatible. In order to safely give someone blood, there are certain things that you need to know. One of those things is the blood type. As we examine blood types the explanation for the risks of un-typed transfusions will become clear.

What are the ABO blood types?

Karl Landsteiner and others discovered two substances (A and B) in blood in 1901 that were antigenic. The discovery earned a Nobel prize in medicine in 1930. Those substances give us the basis for the system of ABO blood typing still in use today. The typing system is also within the capabilities of the technology base of those in Grantville.

The first thing that people working on trying to allow blood transfusions noticed was, that if you mix fresh blood from two people together, sometimes it clumps up into lumps (agglutinates), and sometimes it doesn’t. Not only that, but if you use a centrifuge (or just let the blood set for a while so the heavy bits fall to the bottom, and draw the straw colored plasma off the top) you discover that whole blood from one person can clump up (agglutinate) if you add JUST THE PLASMA from the other person! If you have a large group of people to work with, you can identify four large divisions of clumping rules. This table shows what happens when you add plasma from one person to whole blood from another person. You can see how there are four sets of “types” of reactions between the two elements.

	Aplasma	Bplasma	ABplasma	Oplasma
A blood	OK	Clumps	Clumps	OK
B blood	Clumps	OK	Clumps	OK
AB blood	OK	OK	OK	OK
O blood	Clumps	Clumps	Clumps	OK

Landsteiner and the others figured out that these clumping rules could be explained by the presence of two different substances on the cells, “A” and “B”, and two substances in the plasma, “Anti-A” and “Anti-B”. People with “A” on their cells, and “Anti-B” in their plasma would agglutinate blood cells that had “B” on them. The substances on the red blood cells are called glycoproteins. These chemicals are used by the body to identify “self” or “other” when stuff shows up in the blood. Chemicals performing this function of identifying “self” are called “antigens.” In the plasma of the blood are other chemicals called “antibodies” that attack “foreign” antigens.

Blood is “typed” into four groups, A, B, AB, or O based on what kind of the glycoprotein a person does or doesn’t have on the surface of their red blood cells.

Blood Type	Antigen (on cells)	Antibody (In plasma)	Frequency in the population (U.S.)
A	A	Anti-B	40%
B	B	Anti-A	11%
AB	A and B	None	4%
O	None	Anti-A and Anti-B	45%

Type A blood has only type A glycoprotein on the surface of the red blood cells. Type B blood has only type B glycoproteins. Type AB has both types and Type O (the most common blood type) has neither. The people with group A blood have antibodies to group B and vice versa. So, people with type A blood cannot get blood from anyone with Type B or AB. People with type B cannot get blood from anyone with type A or AB. If they do, the antibodies attaching to the antigens on the blood surface will agglutinate (clump together) and a potentially fatal reaction can occur. Type AB is considered the universal recipient as this blood type can receive blood from any of the other groups. It is the least common of the four types. Type O is the universal donor since it does not have any of the glycoproteins that A, B or AB could react to. In the plasma, the person with group A blood has Anti-B antibodies, B has Anti-A antibodies, AB has neither and O has both.

Positive or Negative blood types

Rh factor (named for the Rhesus monkeys it was discovered in) is another aspect of blood type. It is caused by an antigen on the blood cells, and an antibody in the plasma reacting when put together. There is only one Rh antigen, so the Rh type can only be positive (present) or negative (absent). Landsteiner and Weiner found this positive or negative factor in 1940. There are more than 40 other different antigens but the Rh type D antigen is the one that most significant clinically, and what is being referred to when a simple blood type (B negative for example) is recorded. Approximately 85% of Caucasians, and 95% of African Americans are Rh positive.

Unlike the ABO antigens, people do not come automatically with Rh antibodies. So, a person with the Rh antigen on his or her cells (Rh+) cannot ever have the Rh antibody, or they would clot their own blood. A person who is Rh negative (Rh-) will develop the Rh antibody if they are exposed to the Rh antigen. This can happen through pregnancy or transfusion and is called sensitization. Once sensitized, the person can react to future pregnancies or transfusions.

Women can become Rh sensitized during pregnancy if mother has an Rh negative blood type and baby is Rh positive. Mother and baby are connected in the circulatory system through the placenta. During the pregnancy, the various hormones produced by the placenta suppress the sensitization. However, as soon as the child is born, the suppressing hormones are gone, and the mother is ripe to develop the Anti-Rh antibodies. This means that unless the sensitization is stopped right after the baby’s birth, the mother’s body can react to future pregnancies as “foreign” rather than “self”. The antibodies will attack the baby’s blood cells and the babe could be lost. In the past, babies who survived were treated with transfusions. This can continue to be done down-time. To treat this, the Grantvilliardss will need to include ABO and Rh typing as part of prenatal care to identify at risk moms. Once the medical community develops the ability, the moms can be given an immunoglobin called Rhogam. I’m not sure how long it will take for the Grantvilliards to be able to synthesize this immunoglobin. In the past, babies who survived were treated with transfusions. This can continue to be done down-time.

Rh Positive blood is given to Rh positive persons. Rh negative blood can be given to either or in cases where the Rh factor is unknown, such as emergencies or where the facilities don’t exist to do typing. O negative is considered the universal donor.

How to Determine Whether the Blood is Compatible

Direct and Indirect Compatibility Testing

There are several ways to determine whether or not a recipient’s blood is compatible with the donor’s blood. The reason for performing such testing is to prevent the transfused blood from clumping up inside the recipient, or other transfusion reactions.

The fastest and simplest way to test the blood for compatibility is called an Immediate Spin. It takes about 5 minutes. The technician takes a sample of the recipients blood, and uses a centrifuge to separate the serum from the cells. Then the technician mixes the patient’s serum and donor blood, and allows it to set at room temperature for five minutes. If the blood clumps, the test is positive and the person shouldn’t get that blood. This would be an easy test for Grantvilliards Grantvilliers to do. Even uptime, the Immediate Spin test has been considered sufficient for over 90% of blood transfusions since the 1990s.

If there is time, a second simple test is done uptime, and should be done downtime. This is called a Crossmatch. A crossmatch takes twenty to forty five minutes. A blood donor and recipient may have the same blood type but antibodies on the surface of the red blood cell or in the blood serum may mean that they are not compatible. That is why it is necessary to crossmatch blood that will be transfused. Crossmatching helps to determine whether a given person is able to receive a particular unit of blood. The idea is that if the person’s blood and the unit of blood don’t have a bad reaction in the lab (in vitro), they won’t react badly in the person receiving the blood’s body (in vivo). Reuben Ottenberg in New York developed this procedure in 1907.

There are two types of crossmatches:

The Major crossmatch: This is the most important crossmatch, comparing donor red blood cells (erythrocytes) to recipient serum In this test the technician is checking for preformed (acquired or naturally occurring) antibodies in recipient serum against donor erythrocytes. For the major crossmatch, you need red blood cells from the donor (this can be whole blood from a donor or packed red blood cells) and serum from the recipient

The Minor crossmatch: This compares donor serum to recipient erythrocytes and checks for preformed antibodies in donor serum that could hemolyse recipient red cells. This crossmatch is less important as usually the donor serum is markedly diluted after transfusion and is unlikely to produce a significant transfusion reaction. This type of crossmatch could be important if transfusing small patients or large volumes, in which hemodilution is less likely to occur.

For the major crossmatch: Donor erythrocytes are washed and incubated with recipient serum. For the minor crossmatch: Donor serum is incubated with washed recipient erythrocytes. The mixture of erythrocytes and serum are then observed visually for hemolysis and microscopically for agglutination. Any evidence of agglutination or hemolysis indicates an incompatible crossmatch. When there is an incompatible reaction on the major crossmatch, the donor blood should not be transfused under any circumstances. When there is an incompatible reaction on the minor crossmatch, the transfusion can go ahead. However, if the donated serum is likely to contribute substantially to the plasma volume of the recipient, the serum should be removed from the donor whole blood. The packed cells (washed or unwashed) should be reconstituted in sterile isotonic saline before infusion.

The difference between an immediate spin and a major crossmatch is twofold. First, a major crossmatch uses washed donor red blood cells. That is, after spinning down the RBC’s, they are mixed with a clean saline solution, and spun down again. Second, the incubation time is longer.

R. R. Coombs developed the most common uptime process used for testing compatibility of blood in 1945. Coombs reagent is a solution produced from blood from rabbits which have been sensitized with human antigens. Coombs reagent contains a group of antibodies, primarily Immunoglobulin G and Complement 3 which can latch onto the antigens of any cell which has interesting antigens on its surface. The Coombs reagent is very good at grabbing onto those cells and causing them to clump together quickly.

The people in Grantville should have some of this reagent on hand in the doctor’s offices and be able to make more from that. [[[How?]]] The reagent loses strength over time; so new batches would have to be made. Having people in Grantville who already have known blood types will help make the process easier. Coombs reagent can also be produced from people’s blood. There are two types of Coombs test, direct and indirect.

Direct– Takes about 5-10 minutes

Coombs reagent is combined with the person’s red blood cells. The test is used to see whether there are antibodies on the surface of the red blood cells that would cause a reaction. If there are antibodies found, the blood will agglutinate and the person shouldn’t get that blood as it is not compatible.

Indirect– Takes about 20 minutes

This test uses Coombs reagent to detect red blood cell antibodies in the person’s blood serum. Serum from the patient and Coombs reagent are combined. If there is agglutination of the red blood cells the test is positive. Blood that is negative for those antibodies could be given to the patient. If there are multiple antibodies present or the type of antibodies present is rare, it will be more difficult to match the blood.

Types of Blood, Blood Productions and Uses

There are a number of different products that can result from a blood donation. Whole Blood is blood that has been removed directly from the donor. It can be transfused but has a higher risk of transfusion reactions due to the antibodies in the plasma. Usually, Whole Blood (WB) is now only used in emergencies. Red Blood Cells, also called Packed Red Blood Cells (PRBCs) results when most of the plasma is removed from WB by light centrifugation. After separating the RBC’s from the plasma, the resulting plasma can be centrifuged again to create Platelets and Plasma blood products. Plasma, which does not contain cells, can be stored frozen. Making a centrifuge is very easy. It would also be easy to make the glass test tubes needed in 1632. The test tubes can be capped with cork stoppers.

Here’s where discussion of sodium citrate goes. Won’t have freezers for a while

Blood Products and Their Use
Product	Use	Storage
Whole Blood	Emergency transfusion primarily.	1-6 degrees C for up to 42 days
Contains red blood cells, white blood cells, platelets, and plasma (proteins such as antibodies and globulins). Volume of each unit of WB varies.
Red Blood Cells	Hemorrhage (acute or chronic), some anemias	1-6 degrees C for up to 42 days
Advantages of PRBCs include having less volume than whole blood and less likelihood of an allergic reaction. A unit of PRBCs usually has a volume of 450-500 ml. Each unit of WB or PRBCs should raise an average sized adult’s hemoglobin level by 1 g/dl. One unit contains 160-275 ml of red blood cells (50-60 g of hemoglobin). Since the cells are so “packed” into the solution, it may be necessary to administer a small amount of normal saline to keep the transfusion flowing smoothly. Normal Saline is 0.9% sodium chloride in water.
Fresh Frozen Plasma (FFP)	Those receiving multiple transfusions of PRBCs or WB, those with deficiencies in or of their natural coagulation factors e.g. hemophilia, some liver diseases.	Freezing within 8 hours of collection is necessary to preserve all the clotting factors. FFP should be stored frozen at –18 C or colder, thawed in a water bath using gentle agitation at 30-37 degrees C right before use. It must be used immediately or it can be stored for up to 6 hours at 1-6 C before the transfusion.
Each ml of FFP contains one unit of each anticoagulation factor. FFP also contains albumin (a major plasma protein), fibrinogen, Factor VIII, Factor XIII, and vWF, which are not found in Cryopercipiated blood productcan support the circulatory volume because it contains albumin (a major plasma protein) and help with blood clotting because it has clotting factors. FFP is 91% water, 7% protein and 2% carbohydrate. A standard unit has a volume of 200-250 ml.
Platelets	Platelets help with clotting by sticking to the walls of blood vessels and by clumping together to form a plug or clot. Low volumes of circulating platelets or abnormal functioning platelets are indications for transfusion.	Each unit is 40-70 ml. May be pooled, 6-10 units per transfusion. (see below)
Contains stable clotting factors, some plasma, and sometimes, small amounts of white and/or red blood cells. Each unit of platelets should increase the counts of an average sized adult by 5-10,000/ microliter. Transfused platelets have a short (3-4 day) lifespan.
Cryoprecipitated AHF (Cryo)	Similar to those needing FFP but who don’t need fibrinogen, Factor VIII, Factor XIII, and vWF	Similar to FFP, but uses less often
Contains fewer plasma proteins than FFP, including albumin, and Factors II, V, VII, IX, X, and XI.

Special notes: Pooling and Autologous donation. Blood products such as FFP or Cryo may be pooled, that is, blood from multiple donors put into the same amount of blood to be administered. This is to get enough of the blood product to meet the patient’s needs. The risk of transfusion reactions increase with each additional donor, so the number of donors a particular recipient is exposed to is limited as much as possible.

It is also possible to give blood that will be used at a later time for oneself. This is called autologous donation. There are no transfusion reactions with this kind of donation except possibly, bacterial contamination, with autologous transfusions. These type of transfusions are done most commonly before scheduled surgeries where the expectation is that blood will be needed during or immediately after surgery. A person must make their autologous blood donation several weeks before the surgery.

Eligibility for DonationWho Can Donate Blood?

Blood donors must be in good health. Many people with chronic conditions, as long as the conditions are under control and the person isn’t symptomatic, are still eligible to donate blood. Those under age 17 or who weigh less than 110 lbs may not be able to handle losing the amount of blood necessary to donate one unit of blood and are usually excluded. Donations are usually of one unit at a time when the donor has not donated in at least 56 days.

There are certain ranges of hemoglobin and hematocrit that are acceptable for donation. Rick, do I need to put something in here about what a hemoglobin and hematocrit are? To donate, you must have a hemoglobin at or above 12.5 g/dL. Normal for men is 14-18 gm, for women 12-16 gm. You must also have a hematocrit at or above 38%. Hematocrit is a percentage of hemoglobin found in a given volume of blood. Normal for men is 40-57% (average 47%), women is 37-47% (average 42%).

Blood Donation Process

Both blood donors and blood recipients should have the procedure and risks explained. Risks of donation are minimal. Risks of receiving blood are more complex.

Data collected from the donor should include, temperature, Blood Pressure, hemoglobin and hematocrit levels, history (medical, exposure to diseases, travel, tattoo, medications, chronic health conditions). Donors should drink some fluids before donating.

The donation itself takes about 10 minutes. The donor is seated or reclining during donation and for several minutes afterward. The skin is cleansed by the person taking the blood donation over the site of a large blood vesselvein, usually the antecubital vein(located in the inner part of the arm by the elbow). Alcohol, of which Grantville should have a generous supply, can be used as the skin cleanser. A large bore (usually 18 gauge) sterile needle is attached to tubing and a blood bagbottle. The bag bottle and tubing are sterile inside. Making the needles is a fairly simple manufacturing process and within Grantville and the surrounding area’s capabilities. The bag bottle contains an anticoagulant agent and preservatives. EDTA or sodium citrate are commonly used as preservatives. Most blood products require some form of refrigeration. Most blood products can also be frozen. Refrigeration is going to be an issue in Grantville as is having enough tubing to collect and transfuse the blood.

The needle punctures the skin and then blood vessel. A clamp is released on the tubing and the bagbottle bottle placed below the donor to allow blood to flow out of the donor by gravity. The donor can squeeze their hand below the needle insertion venipuncture site to increase the flow rate of blood into the bagbottle. Usual donation volume is one pint of whole blood (approximately 500ml).

After the donation, the donor is given a salty or sweet snack and fluids (pretzels, cookies, and orange juice are common) to increase the blood volume and begin replacing lost electrolytes and glucose. Some people experience lightheadedness or dizziness after they donate blood but that usually goes away quickly. The fluid loss is usually replaced entirely within 24 hours. The blood loss is usually replaced entirely within 6 weeks.

Blood Administration Process

Before blood is given, the ABO type is verified with the person in the blood bank and the administering nurse. The nurse and a second nurse verify it and the patient’s identity in order to decrease the possibility of an error leading to a Hemolytic transfusion reaction. The patient should have a large bore IV access in place before the transfusion. Sterile IV tubing with an inline filter to catch tiny clots is attached to the blood bagbottle. If necessary (usually for FFP or PRBCs) a bagbottle of normal saline is can also be administered. Normal saline is .9% sodium chloride (a salt) and water. It helps the thick blood products flow into the patient more smoothly. Normal saline is compatible with blood products. Electrolyte containingIV products such as Lactated Ringers solution or hypo or hypertonic IV solutions are not compatible.

The recipient’s vital signs (temperature, pulse, blood pressure, respirations) are taken before the transfusion is begun and at 15 minutes afterwardafter the transfusion starts. Usually at midpoint and the end of a transfusion, vital signs are again taken. Vital signs are compared to previous ones as part of the monitoring for possible transfusion reactions.

Different blood products have different rates at which they are administered. For example, one unit of PRBCs usually takes about 1 ½ to 2 hours to give in an adult. The nurse will adjust the blood flow rate. At the start of the transfusion, the rate is slow, and then increases to the rate it will remain at during the rest of the transfusion after there is no indication of a reaction. The nurse remains with the patient during the first 15 minutes of the transfusion and monitors the patient periodically thereafter.

Transfusion Reactions

What can go wrong?

Transfusion reactions are all the things can go wrong when you try to transfuse blood. Even with the best of intentions, problems arise, and mistakes happen. It is critical that the nursing staff carefully monitor transfusion patients in order to minimize these reactions.

The worst reactions are called Acute Hemolytic Reactions. They occur when the blood types are incompatible, and the recipients serum has an antibody which reacts to an antigen on the blood cells of the donor. The recipients blood cells rupture. This reaction can be fatal. Typical symptoms include chills, shortness of breath, back or chest pain, abnormal bleeding (such as blood in the urine), dropping blood pressure, and increased heart rate.

The risk of this reaction is why transfusions are usually administered very slowly for the first 15 minutes Vital signs and urine are assessed continuously by the nursing staff and are compared to vital signs taken immediately before transfusion began. Acute reactions will usually occur within 15 minutes of initiation of transfusion. If problems are noted, the transfusion is stopped immediately, and non-blood based IV fluids are provided to dilute the “bad blood.” Uh, not exactly Rick. They’re provided to mitigate the hemodynamic collapse. We can talk more about this on the phone. Delete his why sentence and replace it with mine

The next common transfusion problem is a Febrile Nonhemolytic reaction. In one-half to one percent of transfusion recipients, a reaction to white blood cells in the fluid transfused occurs. The recipient has antibodies to white blood cells in the donor’s blood. In people who are sensitive, those cells can be reduced in the blood administered to the recipient. Symptoms include a temperature rise of 1 degree C and chills. Treatment for these reactions is primarily supportive such as administration of antipyretics (medications such as aspirin that help lower a fever). These reactions make a person feel badly but aren’t fatal.

About one percent of transfusion recipients have an allergic reaction to the blood they receive. Allergic reactions can range from fairly minor symptoms such as itching or rash to a full-blown anaphylaxis. Treatments are supportive such as medication for fever or allergy. Antihistamines, steroids and epinephrine may be given. Grantville can make epinephrine or epinephrine like substances but I’m not sure the tech base exists to make antihistamines or steroids. Rick, just a FYI, steroids may be possible from animal tissue but that is probably 5 years in GV’s future.

In less than one transfusion in five thousand, the recipient’s blood plasma has antibodies to the donor’s white blood cells. The result is that enzymes are released which cause fluids to leak from the vascular space into the lungs, causing pulmonary edema. Treatments for pulmonary edema are directed toward reducing the fluid in the lungs with diuretics, limiting fluid intake, and aggressively supporting pulmonary function by such measures as oxygen administration. Can you put the name of the reaction back in? Yes I can

People receiving plasma products are most at risk for this type of reaction. Reactions of this sort usually occur within 6 hours of transfusion.

The supportive therapy for pulmonary edema can sometimes get very complex. Grantville may have difficulty providing the more complex therapies needed for someone with this type of reaction.

Sometimes, the amount of blood given to the recipient is more then the recipient’s body can handle. This can also be due to blood being infused too quickly. Circulatory overload can be avoided by giving blood in smaller amounts over longer periods of time to those at risk or who exhibit signs of circulatory overload. Diuretics can be given to help reduce the volume. PRBCs and other more concentrated blood products are given to these persons. All of these should be within the capabilities of Grantville to handle if caught early enough.

Finally, there is the possibility that the blood product being transfused is contaminated. Prevention and early detection of infection in the blood is very important. Bacteremia (bacteria in the blood), also called sepsis, can be fatal. Preventative measures include maintaining sterile technique throughout the process and storing blood at appropriate temperatures. Nursing staff can assure that treatment for contamination starts as early as possible through assessment of patient condition and vital signs. Early signs are sudden onset of high fever, severe chills, lowering of blood pressure. Sepsis can lead to circulatory collapse.

In addition, the recipient can acquire blood borne infections such as cytomegalovirus, hepatitis B or C and so on from the transfusion. Grantville probably won’t have blood screening tests for all the blood borne infections possible by 1633 but they should within another 5 years.

Conclusion

Many challenges face the Grantville medical staff. Blood transfusion is a major part of modern medical practice. They will need to find replacements for much of the reagents, and equipment that they are used to relying on. Despite those challenges, they have a wealth of knowledge which can allow them to provide a level of medical treatment unknown downtime. The Grantville medical communities understanding of the nature of blood chemistry and their experience should allow blood transfusion to begin immediately upon their arrival.

References

http://www.redcross.org/flash/giftoflife/giftoflife.html

http://www.aabb.org/All_About_Blood/COI/coi0702.pdf

http://www.itxm.org/TMU2000/tmu10-2000.htm

http://matcmadison.edu/is/hhps/mlt/mljensen/BloodBank/lectures/crossmatch.htm

http://medlib.med.utah.edu/WebPath/TUTORIAL/BLDBANK/BBTXRXN.html

Taber’s Cyclopedic Medical Dictionary, 17^th Ed. F.A. Davis, Philadelphia.

Joyce M. Black and Esther Matassarin-Jacobs, Luckmann and Sorensen’s Medical-Surgical Nursing, A Psychophysiolic Approach. 4^th ed. W B Saunders, Philadelphia.

http://www.itxm.org/Archive/tmu1-94.htm

http://pathcuric1.swmed.edu/Resident_Docs/Resident%20Call%20Manual/TRNF/TRNFDATT.HTML

http://matcmadison.edu/is/hhps/mlt/mljensen/BloodBank/Lab_Manual/antibody_screening.htm

 

Glossary

Definitions of medical terms used in this FAQ are presented first to make the FAQ more understandable. Some definitions are also included in the text itself.

Agglutination-

This is a type of antigen-antibody reaction. See antigen and antibody definitions. Antibodies attach the antigens on the surface of the red blood cell of a different blood type, causing it to clump together.

Albumin-

The main protein found in blood.

Anemia-

A lowering the amount of red blood cells circulating in the blood stream. There are many types and causes, some of which can be helped by transfusions.

Antibody-

Immune globulins produced by a type of white blood blood cell called a B lymphocyte in response to the presence of an antigen. Antibodies are complex glycoproteins that fight infection.

Antigen-

A protein marker on the cell’s surface that tells the body the cell is part of the body and not a foreign invader such as a germ. Without that identifying marker, the body couldn’t tell when antibodies were needed to fight off infection.

Circulatory System-

Heart and blood vessels (arteries, veins, capillaries).

Centrifuge-

A mechanical device that spins test tubes at high speeds. Centrifugal force causes the heavier particles in a liquid to go to the bottom and the lighter particles to go to the top of the test tube. Plasma is lighter than red blood cells, so plasma goes to the top, and red blood cells to the bottom. White blood cells are lighter than red but heavier than plasma so they go in the middle. That’s how whole blood gets split into different blood products.

Disseminated Intravascular Coagulation (DIC)-

An abnormal form of blood clotting where blood begins clotting all over the body rather than in one local place in response to an injury. Some of the factors that the body needs to make blood clots get all used up in the abnormal clotting process. Then the person begins to bleed because they don’t have enough free clotting factors left. Many things can cause DIC including trauma and sepsis.

(Blood) Donor-

Person who gives the blood.

Factor (roman numeral)-

A group of proteins that are essential to normal blood clotting.

Febrile-

Related to fever.

Fibrinogen-

A blood protein in the plasma that helps make a blood clot (also called Factor I).

Hemolytic-

The destruction or breakdown of red blood cells

Immuneglobulin-

A group of similarly made proteins that can act as antibodies.

Plasma-

The liquid part of the blood and the lymph which contains serum, proteins, red and white blood cells and chemical substances such as oxygen, glucose and electrolytes.

Platelet-

A tiny substance in the blood that helps blood to coagulate by sticking to each other around the area of an injury or a blood vessel wall to form a patch (blood clot) and stop bleeding.

(Blood) Recipient-

Person who receives a transfusion.

Red Blood Cell-

The blood cell which contains hemoglobin. Red blood cells are also called erythro (red) cytes (cells).

Sensitization-

A process that results in the body being susceptible to an immune process involving antigens and antibodies. It requires at least one previous exposure to the substance that is the trigger for the sensitive reaction.

Sepsis-

The condition occurs when germs or their byproducts get into the blood stream. Usually, the person will have a fever but not always.

Transfusion-

An injection of blood or a blood product into a vein for a theraputic purpose.

White Blood Cell-

A group of blood cells that fight infection in the body in different ways.